WASHINGTON
— Regardless of which candidate wins the Democratic primary battle next year, one thing is already clear: The eventual nominee will most likely be a sitting member of Congress.

For Democrats, this may present a challenge. Only two candidates in the past century have gone directly from Congress to the White House: John F. Kennedy and Warren Harding. Yet with Sen. Joseph Lieberman of Connecticut expected to enter the race today, the field of Democratic contenders for 2004 looks to be dominated by lawmakers.

Along with Senator Lieberman, the group of congressmen-turned-candidates includes Sens. John Kerry of Massachusetts and John Edwards of North Carolina, along with Rep. Richard Gephardt of Missouri. Sen. Bob Graham of Florida is weighing a run, as are Sens. Christopher Dodd of Connecticut and Joseph Biden of Delaware.

Certainly, it's not unusual for members of Congress to hold presidential ambitions. But while many of these candidates boast notable legislative accomplishments and years of public service, analysts say they will also face significant hurdles. These range from scheduling conflicts - finding themselves stuck on the Hill when they'd rather be out campaigning - to having to explain the votes they cast on any number of controversial bills likely to come up over the next year and a half.

"It's a problem having all these senators," says Stuart Rothenberg, a political analyst in Washington. "They're going be placed in the awkward position of having to support the president or oppose him - and they're going to be jockeying with one another."

The governors' edge

Since Kennedy won the White House in 1960, only three Senators have even captured their party's nomination: Republicans Barry Goldwater and Bob Dole, and Democrat George McGovern, all of whom went on to lose the general elections - badly.

But this year, the Democrats may not have much choice. With former Vice President Al Gore out of the race, the only nonlegislators running so far are former Gov. Howard Dean of Vermont and the Rev. Al Sharpton of New York. Both are considered by many to be long shots - though their unique outsider status could also prove an unexpected source of strength.

It's no accident that four of the past five presidents have come from governors' mansions. For one thing, the widespread distrust of Washington has often led voters to prefer candidates who live and work in the states.

In addition, governorships can seem natural training grounds for the presidency, since both are executive positions. Governors can talk about managing budgets and claim credit for specific accomplishments in their states - while lawmakers are left discussing bills they've cosponsored.

The problem, analysts say, is that Democrats simply don't have a strong roster of governors who could run. Throughout the 1990s, Republicans dominated the governorships of many of the biggest states - though Democrats recaptured several this past November. And the few Democratic governors who had seemed positioned to move onto the national stage wound up in unexpectedly tough races: California Gov. Gray Davis, for example, barely won reelection after his perceived mishandling of the state's energy crisis, while Georgia Gov. Roy Barnes was ousted in a surprise upset.

An unusual year?

Still, some strategists argue that 2004 might prove an unusual year, and that the current climate might actually favor members of Congress.

Given concerns about terrorism and the economy, voters may place a premium on political experience and not regard Washington in such a negative light. When it comes to foreign-policy issues in particular, congressmen are far more likely to have experience than governors, which could prove a valuable asset this cycle.

"In a time of economic crisis and national security threats, I think people are going to look for leadership that has experience dealing with those sets of issues," says Craig Smith, a top adviser to the Lieberman campaign. "Other than the president of the United States, members of Congress are the only group that have extensive experience in both national security and economic issues."

Still, Mr. Smith acknowledges that Democrats must present themselves as candidates for change, even if they're currently part of the institution they're criticizing. "Any candidate who goes out there and says, 'I think government's working just fine and dandy and I don't want to change a thing,' is going to be pretty much of a nonstarter," he says.

But the most important factor may have less to do with the nominee than with developments in the economy and national security. The Democratic field looks strong enough, say observers, to topple Mr. Bush - if he suddenly finds himself vulnerable.

"It's an interesting, credible field that could produce a winner if Bush is held in low esteem a year and a half from now," says Mr. Rothenberg. "If Bush is popular, Democrats could nominate the second coming of John Kennedy and lose."